Bax translocation to mitochondria (99) and Bax-dependent caspase-3 activation (100) are critical events for neuronal PCD apoptosis in in vitro systems. In ALS, we have found that caspase-3 activity is elevated, DFF45 is activated, and internucleosomal fragmentation of DNA occurs. Therefore, an inappropriate re-emergence of a PCD mechanism, involving cytosol-to-membrane and membrane to-cytosol redistributions of cell death proteins, participates in the pathogenesis of motor neuron degeneration ALS (23,98).